Wire musical instrument strings, as for banjos, guitars, etc., normally have one end terminated by a so-called ball. Such a ball normally is hollow, has a coaxial through-hole and has a substantially cylindrical outer peripheral surface with an annular groove intermediate its ends which snugly receives a loop of the wire closed by twisting of the wire immediately adjacent such loop and ball. Such ball thus forms an enlargement at the end of the wire string by which the latter can be fixed to a member on the body of the musical instrument and from which the wire extends to connect at its unballed end to a tuning key or the like at the head of the instrument.
In a prior machine for securing one end of a wire musical instrument string to a ball with a twist, the wire is fed behind the ball tangential to the groove therein, the ball is moved rearwardly from the wire path to form a U-shape around the ball, the trailing end of the wire is severed to form the short leg of the U-shape, the legs are clamped and the ball is rotated to form such twist (hereinafter referred to as a single twist), whereafter the interconnected ball and wire are ejected from the machine.
While such prior machine has for the most part been satisfactory in terms of formation of such a single twist, the present invention is the result of a continuing effort to achieve improved performance and reliability of operation of producing a ball-ended musical instrument string of desired length wherein the finished product may be provided, if desired, with an additional lock twist and/or a flattened wire cross section without recourse to transfer to or from other machines.
Accordingly, the objects of this invention include provision of:
1. A ball-ender apparatus for securing an annular ball to a wire musical instrument string rapidly and reliably.
2. Apparatus, as aforesaid, permitting friction drive wire feeding without slippage from a relatively high inertia rotative supply reel or the like by limiting wire starting and feeding tension yet preventing reel overrun when feeding stops, in which the length of wire fed is readily and reliably adjustable through relocation of the friction drive interface between a timing wheel and a rotating portion of the wire drive, and in which the wire may be subjected to flattening as it approaches the ball.
3. Apparatus, as aforesaid, which provides for reliable feeding and location of a ball adjacent the wire path and which is capable of handling ball of varius lengths.
4. Apparatus, as aforesaid, capable of forming merely a single twist or a single twist plus a lock twist, as desired, and with only a minimal amount of additional structure required for provision of the lock twist, with changeover time under 5 minutes.
5. Apparatus, as aforesaid, in which clamping of wire ends for producing the first twist is readily adjustable for differing wire diameters and varying time of occurrence of clamping action, as well as permitting close interlocation of main and twist clamping members for engaging the same wire ends to effect both types of twist in a single ball end connection.
Other objects and purposes of this invention will be apparent to persons acquainted with apparatus of this general type upon reading the following specification and inspecting the accompanying drawings.